Plants need boron for proper health, but it's not known whether humans do. However, boron does seem to assist in the proper absorption of calcium, magnesium, and phosphorus from foods, and slows the loss of these minerals through urination. Very preliminary evidence suggests that boron supplements may be helpful for
osteoarthritis
and
osteoporosis
.

Sources

No dietary or nutritional requirement for boron has been established, and boron deficiency is not known to cause any disease. Good sources include leafy vegetables, raisins, prunes, nuts, non-citrus fruits, and grains. A typical American daily diet provides 1.5 to 3 mg of boron.

Therapeutic Dosages

When used as a treatment for osteoarthritis or osteoporosis, boron is often recommended at a dosage of 3 mg per day, an amount similar to the average daily intake from food. However, food sources may be safer (see
Safety Issues
).

Therapeutic Uses

Boron aids in the proper metabolism of vitamins and minerals involved with bone development, such as
calcium
,
copper
,
magnesium
,
and
vitamin D
.
4,10,14-18
In addition, boron appears to affect estrogen and possibly testosterone as well, hormones that affect bone health.
4,10,19
On this basis, boron has been suggested for preventing or treating
osteoporosis
. However, there have been no clinical studies to evaluate the potential benefits of boron supplements for any bone-related conditions.

On the basis of similarly weak evidence,
2,6
boron is often added to supplements intended for the treatment of osteoarthritis.

Boron has also been proposed as a
sports supplement
, based on its effects on hormones.
20
However, studies have, as yet, failed to find evidence that it helps increase muscle mass or enhances performance.
21,22

One large observational study suggests that higher intake of boron may reduce risk of prostate
cancer
.
5

Finally, boron is sometimes recommended as a treatment for
rheumatoid arthritis
, but there is no evidence to support this use.

What Is the Scientific Evidence for Boron?

Osteoarthritis

In areas of the world where people eat relatively high amounts of boron—between 3 and 10 mg per day—the incidence of osteoarthritis is below 10%.
6
However, in regions where there is less boron in the diet—1 mg or less per day—the incidence of arthritis is much higher. In addition, the joints of people with osteoarthritis have been found to contain less boron than people without the condition. These observations have given rise to the hypothesis that boron supplements might be helpful for people who already have arthritis symptoms.

However, the only direct evidence that it works comes from one highly preliminary study reported in 1990.
7

Osteoporosis

In one small study, 13 postmenopausal women were first fed a diet that provided 0.25 mg of boron for 119 days; then they were fed the same diet with a boron supplement of 3 mg daily for 48 days.
9
The results revealed that boron supplementation reduced the amount of calcium lost in the urine. This suggests (but certainly doesn't prove) that boron can help prevent osteoporosis.

However, in a similar study, boron administration did not affect urine calcium loss.
10
Another study found that boron fails to affect calcium loss among people who receive enough magnesium.
23

Safety Issues

Since the therapeutic dosage of boron is about the same as the amount you can get from food, it is probably fairly safe. Unpleasant side effects, including nausea and vomiting, are only reported at about 50 times the highest recommended dose.

One potential concern with boron regards its effect on hormones. In at least two small studies, boron was found to increase the body's own estrogen levels, especially in women on estrogen-replacement therapy.
11,12
Because elevated estrogen increases the risk of breast and uterine cancer in women past menopause, this may be a matter of concern for those who wish to take supplemental boron. Further research is necessary to discover whether boron's apparent effect on estrogen is a real problem or not. At the present time, we would recommend getting your boron from fruits and vegetables: a large study found that high intake of boron from these sources did not affect breast cancer rates.
13

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.